Nissan Pathfinder R51 Aventura - Black smoke

Honest John Back Room » Technical matters
View Threaded
Thu 28 Aug 2014 10:27
Nissan Pathfinder R51 Aventura - Black smoke - adriaman

Hi everyone

I have a 2008 R51 Aventura with a black smoke problem

It has just had four new (yes, NEW) injectors and a suction control valve 200 miles ago.

It starts easily and runs well. It is returning aroung 34mpg solo and 27.5mpg with an 1800kg caravan on the hook.

It will occasionally cut out shortly after starting up and then takes 20ish turns to re-start, hence the reason for fitting the suction control valve, which hasn't cured the problem.

When changing up or when at low revs, it will give a big puff of black smoke, especially with the caravan on. It black smokes continuously when climbing with the caravan on.

The injectors and suction control valve were fitted by a very reputable firm in Manchester but it has had little effect on the vehicle. Of the original injectors, three were overfuelling and one was underfuelling. Any help would be really appreciated.

Reply | Report as offensive | Link
Thu 28 Aug 2014 13:17
Nissan Pathfinder R51 Aventura - Black smoke - Peter.N.

Unless the fuel consumption has dropped drastically I would say the most likely cause is accumulated soot in the exhaust system. If you give it a good blast it should clear it out, if it doesn't smoke after that you probably don't have a problem.

Reply | Report as offensive | Link
Thu 28 Aug 2014 13:43
Nissan Pathfinder R51 Aventura - Black smoke - elekie&a/c doctor
I think I would be looking at a possible egr valve problem here.
Reply | Report as offensive | Link
Thu 28 Aug 2014 23:43
Nissan Pathfinder R51 Aventura - Black smoke - The-Mechanic

Black smoke is either too much fuel being injected or not enough air (oxygen) to complete combustion.

The EGR valve could be allowing too much "dirty" air that has little oxygen in it back into the intake reducing it's efficiency. The air filter if clogged with dirt will also reduce air flow as will kinked / collapsed intake air hoses.

A clogged oxidising catalyst will also cause too much back pressure and can cause intake air flow to "back up" giving the same impression as a blocked intake system. There is also the possibility the fuel pressure regulator is faulty and over pressurising and therefore over fuelling the injectors.

Then there's a chance the air mass meter is reading incorrectly or a wiring fault to / from the ECU is giving incorrect signals causing an over fuel situation.

Best advice is get it looked at by a diesel specialist. Most garages won't have the equipment or expertise to fault find in situations such as this and if they do take on the job, the majority will sub let it out to their local specialist anyways.

Reply | Report as offensive | Link